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1.
The flowering of Lemma perpusilla grown on half-strength Hutner's medium with sucrose under inductive photo-periods is inhibited in a periodic manner by daily transfers to water for short periods of time. The phase of maximal inhibition of flowering caused by water treatment is about 1 to 2 hours after the time of maximal sensitivity to light pulses. The rhythm of sensitivity to water treatments does not persist under continuous blue light. Supplementing the water with either Ca(NO3)2 or K2HPO4 partially reverses the inhibition of flowering, with the first salt being more effective. Supplementation with NH4NO3 or MgSO4 increases the inhibition. The water effect on flowering is not observed in plants grown on half-strength Hutner's medium without sucrose. The water treatments may act by removing or destroying a crucial precursor for photoperiodic induction, with the other conditions modifying permeability. The system provides a new technique for investigating the mechanism of photoperiodic induction.  相似文献   

2.
The effect of two nutrient solution temperatures (cold (10 °C) and warm (22 °C)) during two flowering events of rose plants (Rosa × hybrida cv. Grand Gala) were examined by measuring chlorophyll (Chl) a fluorescence, ammonium (NH4+) content and nitrate reductase (NR) activity in four different leaf types, that is, external and internal leaves of bent shoots and lower and upper leaves of flowering stems. Besides, nitrate (NO3?) uptake and water absorption, total nitrogen (N) concentration in the plant, dry biomass, and the ratios of shoot/root and thin-white roots/suberized-brown roots were determined. Generally, cold solution increased NO3? uptake and thin-white roots production but decreased water uptake, so plants grown at cold solution had to improve their NO3? uptake mechanisms to obtain a higher amount of nutrient with less water absorption than plants grown at warm solution. The higher NO3? uptake can be related to an increase in NR activity, NH4+ content and total N concentration at cold solution. Nutrient solution temperature also had an effect on the photosynthetic apparatus. In general terms, the effective quantum yield (?PSII) and the fraction of open PSII reaction centres (qL) were higher in rose plants grown at cold solution. These effects can be associated to a higher NO3? uptake and total N concentration in the plants and were modulated by irradiance throughout all the experiment. Plants could adapt to cold solution by enhancing their metabolism without a decrease in total dry biomass. Nevertheless, the effect of nutrient solution temperature is not simple and also affected by climatic factors.  相似文献   

3.
1. Ca and K condition the irritability of Pelagia both in regard to rhythmical contractions and general luminescence. If either ion is omitted from the solution conduction of stimuli for pulsations and luminescence does not occur, although local responses still persist. 2. When Mg is omitted from the solution, Pelagia shows hyper-irritability with respect to rhythmical contraction and general luminescence. This is referable to the unantagonized action of K and Ca ions. 3. Exposure to the carbon arc suppresses general luminescence, the effect depending upon the quantity of light i.e. intensity x time of exposure. 4. The luminescent material secreted by Pelagia is inactive in sea water, but when put into salt solutions is activated by some of them. The efficiency of the salts, measured by brightness of light, is in the following order: MgSO4, K2SO4, Na3 citrate, KCl, BaCl2, SrCl2, CaCl2, and LiCl while NaCl and MgCl2 act as inhibitors. 5. Acidity inhibits the reaction, alkalinity promotes it. NH4OH in concentrations 0.27 N to 0.9 N causes luminescence for 10 minutes at 20°. 6. The average temperature coefficient for the reaction of the luminescent substance when activated by ammonia or MgSO4 is 2.18 for a temperature interval of 10°C. 7. The luminescence reaction cannot be the result of cytolysis, because (a) raising the temperature of sea water in which luminous material is immersed does not cause luminescence, although sufficient to produce cytolysis. (b) The salt solutions used in our experiments to cause luminescence, do not act cytolytically on cells in general.  相似文献   

4.
Micropropagation of hazelnut (Corylus avellana L.) is typically difficult because of the wide variation in response among cultivars. This study was designed to determine the required mineral nutrient concentrations for micropropagation of C. avellana cultivars using a response surface design analysis. Driver and Kuniyuki Walnut (DKW) medium mineral nutrients were separated into five factors: NH4NO3, Ca(NO3)2, mesos (MgSO4 and KH2PO4), K2SO4, and minor nutrients (boron, copper, manganese, molybdenum, and zinc) ranging from 0.5× to 2× the standard DKW medium concentrations with 33 treatments for use in modeling. Overall quality and shoot length for all cultivars were influenced by ammonium and nitrate nitrogen, mesos and minors. Reduced Ca(NO3)2 improved multiplication while higher amounts increased shoot length for most cultivars. Uptake of nutrients varied among the cultivars. Calcium and magnesium concentrations were greater in the shoots that grew well compared to poorly-growing and control treatments. All five cultivars showed improved growth on some treatments and the models indicated that shoots grown on an optimized medium would be even better. This model indicates that NH4NO3, Ca(NO3)2, mesos, and minors all had significant effects on hazelnut growth and multiplication and should be optimized in future experiments.  相似文献   

5.
Self-grafted and pumpkin rootstock-grafted cucumber plants were subjected to the following four treatments: 1) aerated nutrient solution alone (control), 2) nutrient solution with 10 mM Ca(NO3)2 (Ca), 3) nutrient solution with 90 mM NaCl (NaCl), and 4) nutrient solution with 90 mM NaCl + 10 mM Ca(NO3)2 (NaCl+Ca). The NaCl treatment decreased the plant dry mass and content of Ca2+ and K+ but increased the Na+ content in roots and shoots. Smaller changes were observed in pumpkin rootstock-grafted plants. Supplementary Ca(NO3)2 ameliorated the negative effects of NaCl on plant dry mass, relative growth rate (RGR), as well as Ca2+, K+, and Na+ content especially for pumpkin rootstock-grafted plants. Supplementary Ca(NO3)2 distinctly stimulated the plasma membrane (PM) H+-ATPase activity which supplies the energy to remove excess Na+ from the cells. The expressions of gene encoding PM H+-ATPases (PMA) and gene encoding a PM Na+/H+ antiporter (SOS1) were up-regulated when Ca(NO3)2 was applied. The pumpkin rootstock-grafted plants had higher PM H+-ATPase activity as well as higher PMA and SOS1 expressions than the self-grafted plants under NaCl + Ca treatment. Therefore, the addition of Ca2+ in combination with pumpkin rootstock grafting is a powerful way to increase cucumber salt tolerance.  相似文献   

6.
This study investigated the effect of CaCl2 and Ca(NO3)2 on fungal growth of Phytophthora sojae isolates, disease reduction on two cultivars of Glycine max (L.) Merr. cv. Chusei‐Hikarikuro (black soybean) and cv. Sachiyutaka (white soybean) and zoospore release. A concentration of 20–30 mm CaCl2 or 30 mm Ca(NO3)2 led to a slight decrease of the growth rate of two isolates on PDA; however, 0.4 and 4 mm of CaCl2 and Ca(NO3)2 increased growth. The application of 4 mm CaCl2 or more than 4 mm Ca(NO3)2 before inoculation greatly inhibited infection in the two soybean cultivars. Disease suppression recorded in laboratory experiments using pathogen mycelium was because of the response of plant tissues rather than a direct inhibition of pathogen hyphal growth by the application of calcium. Furthermore, Ca(NO3)2 was more effective than CaCl2. The calcium contents in plants increased at the time of inoculation. The extent of disease reduction was related to an increased calcium uptake by plants of the two cultivars, except for some cases involving cv. Chusei‐Hikarikuro. Results showed that the effective element in reducing Phytophthora stem rot was calcium and that differences existed between the two cultivars in terms of the mechanisms of calcium uptake and the effect on disease suppression. The presence of 4–30 mm CaCl2 and Ca(NO3)2 decreased the release of zoospores from isolates on lima bean agar, although 0.4 mm CaCl2 and Ca(NO3)2 significantly induced zoospore release. These results suggest the possibility of applying a solution containing more than 4 mm of calcium to decrease the incidence of disease in agricultural fields by the inhibition of zoospore release.  相似文献   

7.
8.
Brewbaker, James L., and Beyoung H. Kwack. (U. Hawaii, Honolulu.) The essential role of calcium ion in pollen germination and pollen tube growth. Amer. Jour. Bot. 50(9): 859–865. Illus. 1963.—A pollen population effect occurs whenever pollen grains are grown in vitro. Small pollen populations germinate and grow poorly if at all, under conditions which support excellent growth of large pollen populations. The pollen population effect is overcome completely by a growth factor obtained in water extracts of many plant tissues. This factor is shown to be the calcium ion, and its action confirmed in 86 species representing 39 plant families. Other ions (K+, Mg++, Na+) serve in supporting roles to the uptake or binding of calcium. The high requirement of calcium (300–5000 ppm, as Ca (NO3)2·4H2O, for optimum growth) and low calcium content of most pollen may conspire to give calcium a governing role in the growth of pollen tubes both in vitro and in situ. It is suspected that ramifications of this role extend to the self-incompatibilities of plants and to the curious types of arrested tube growth distinguishing, for example, the orchids. A culture medium which proved its merit in a wide variety of pollen growth studies included, in distilled water, 10% sucrose, 100 ppm H3BO3, 300 ppm Ca (NO3)2·4H2O, 200 ppm MgSO4·7H2O and 100 ppm KNO3.  相似文献   

9.
Two soils, contaminated by sludge application or by smelter activities, have been amended with : lime (CaO), lime + Al-pillared smectites (CaO + Sm), phosphate basic slags (SCO), manganese oxide (HMO), iron oxide (HFO) and steel shot (GA). Four single soil extractions (water, 0.1 M Ca(NO3)2 0.05 M ED TA-NH4 and acetic acid (0.43 M HAc)) and the two plant cultures (tobacco and ryegrass) were used to evaluate the effect of these inorganic additives on the mobility and plant-availability of cadmium in the soils. The Cd extracted by the different solutions was compared to the concentration of Cd in the shoots of ryegrass and tobacco. The effect of treatments on Cd mobility in soil was easily discriminated by the use of either water or Ca(NO3)2. The addition of HMO and GA reduced both the mobility and the phyto-availability of Cd in the two soils. Conversely, the alkaline additives and HFO decreased the Cd mobility, but not the Cd plant availability. Single soil extractions using either water or Ca(NO3)2 are a useful tool for estimating Cd immobilization, but not sufficient for assessing Cd plant availability ; a validation by plant tests must be conducted.  相似文献   

10.
The effects of Ni(NO3)2 and Pb(NO3)2 on Amaranthus sp. L. root growth and the effect of calcium on heavy metal (HM) accumulation in the growing root zone and root growth inhibition were studied. The seeds were germinated in the Pb(NO3)2 solutions at concentrations of 50, 100, 200, 500 and 700 μM or Ni(NO3)2 solutions at concentrations of 10, 50, 70, 100, and 500 μM in the presence of 100 μM Ca(NO3)2 or without it. HM toxicity was assesses in 7 days after seed sowing by the root length. Distribution of HM over the tissues of the growing root part was examined histochemically. Ni was more toxic to root growth than Pb. In the presence of Ca, Ni and Pb accumulation in the amaranth root growing part increased markedly, and this enhanced their growth-inhibitory of action. A comparison of results obtained in this work and available from the literature permitted a conclusion that the routes of HM penetration into the root differ in different plant species, and this determines ambiguity of protective Ca action.  相似文献   

11.
Soil water deficit is a major limitation to agricultural productivity in arid regions. Leaf photosynthesis can quickly recover after rewatering and remains at a higher level for a longer period, thus increasing crop yield and water-use efficiency (WUE). We tested our hypothesis that leaf photosynthesis and root activity of water-stressed cotton (Gossypium hirsutum L.) plants could quickly recover after rewatering at a certain growth stage and it should not influence a cotton yield but increase WUE. Treatments in this study included two degrees of water stress: mild water stress (V1) and moderate water stress (V2) imposed at one of four cotton growth stages [i.e., S1 (from the full budding to early flowering stage), S2 (from early flowering to full flowering), S3 (from full flowering to full bolling), and S4 (from full bolling to boll-opening)]. The soil water content before and after the water stress was the same as that in the control treatment (CK, 70–75% of field capacity). Water deficit significantly reduced the leaf water potential, net photosynthetic rate, and stomatal conductance in cotton. The extent of the decline was greater in S2V2 treatment compared to others. Water deficit also reduced root activity, but the extent of inhibition varied in dependence on soil depth and duration. When plants were subjected to S1V1, the root activity in the 20–100 cm depth recovered rapidly and even exceeded CK one day after rewatering. An overcompensation response was observed for both photosynthesis and aboveground dry mass within one to three days after rewatering. Compared with the CK, S1V1 showed no significant effect on the yield but it increased total WUE and irrigation WUE. These results suggest that even a short-term water stress during the S1, S2 and S4 stages mitigated, with respect to the root activity, the negative effect of drought and enhanced leaf photosynthesis compensatory effects of rewatering in order to increase cotton WUE with drip irrigation under mulch in arid areas.  相似文献   

12.
The antimicrobial activity of strainsBacillus megaterium NB-3,Bacillus cereus NB-4,Bacillus cereus NB-5,Bacillus subtilis NB-6 andBacillus circulans NB-7, previously isolated from the air flora, now in the Jerash Culture Collection (Jordan), was investigated in media containing different nitrogen sources. Maximum antimicrobial activity of strains NB-4, NB-5 and NB-6 was observed using Ca(NO3)2 as nitrogen source, (NH4)2SO4 and KNO2 strongly enhanced the antimicrobial activity of strains NB-3 and NB-7, respectively. The lowest level of the antimicrobial activity of strains NB-4 and NB-5 was observed using NaNO3. In case of strains NB-3, NB-6 and NB-7, the lowest antimicrobial activity was observed using NH4NO3, KNO3 and (NH4)2SO4 as nitrogen source, respectively.  相似文献   

13.
Toxic Effect of Cadmium on Rice as Affected by Nitrogen Fertilizer Form   总被引:1,自引:0,他引:1  
A nutrient solution experiment was conducted to determine the influence of N forms on growth, oxidative stress, and Cd and N uptake in rice plants. The treatments were consisted of two Cd levels (0 and 1 μmol) and three N forms (NH4)2SO4, NH4NO3 and Ca(NO3)2. The results indicated that without Cd addition in the culture solution, the N forms had no significant effect on all measured parameters, including plant growth, photosynthetic traits, malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity, and Cd and N concentration, while Cd addition in the medium resulted in significant differences in measured parameters among the three forms of N fertilizers. The least inhibition of growth was noted in (NH4)2SO4-fed plants, and the largest in Ca(NO3)2-fed plants, when plants were exposed to Cd stress. The highest photosynthetic rate and chlorophyll content was also recorded in (NH4)2SO4-fed plants. Addition of Cd caused a remarkable increase in SOD activity and MDA content in plants, and the extent of increase varied with N form, with (NH4)2SO4-fed plants being smallest. In comparison with the control plants, the N concentration in roots and shoots was not significantly affected in (NH4)2SO4-fed plants, but significant decrease in root N concentration was found for the NH4NO3 and Ca(NO3)2-fed plants under Cd stress. Moreover, the significant differences were also noted among the three N forms in both root and shoot Cd concentrations, with (NH4)2SO4-fed plants being the lowest. The results indicated that the toxic effect of Cd on rice varied with the form of N fertilizer.  相似文献   

14.
The effect of nitrogen forms on photosynthesis and anti-oxidative systems of barley plants under chromium stress was studied in a hydroponic experiment. The treatments comprised three chromium concentrations (0, 75, and 100 μM) and three N forms (NH4)2SO4, urea, and Ca(NO3)2. In comparison with the urea or (NH4)2SO4 fed plants, the Ca(NO3)2 fed plants had higher net photosynthetic rate, intercellular CO2 concentration, stomatal conductance, transpiration rate, photosynthetically active radiation utilization efficiency, variable to maximum chlorophyll fluorescence ratio, and the content of chlorophylls and carotenoids. Cr toxicity caused oxidative stress in all plants but the Ca(NO3)2 fed plants had the least oxidative stress. Moreover, the Ca(NO3)2 fed plants had higher activities of anti-oxidative enzymes and content of non-enzymatic antioxidants than the urea or (NH4)2SO4 fed plants. In addition, the Ca(NO3)2 fed plants had higher N and lower Cr content in all plant tissues than the urea or (NH4)2SO4 fed plants. The current results indicate that the reasonable choice of N fertilizer is important for barley production on the Cr-contaminated soils.  相似文献   

15.
Defining optimal mineral-salt concentrations for in vitro plant development is challenging, due to the many chemical interactions in growth media and genotype variability among plants. Statistical approaches that are easier to interpret are needed to make optimization processes practical. Response Surface Methodology (RSM) and the Chi-Squared Automatic Interaction Detection (CHAID) data mining algorithm were used to analyze the growth of shoots in a hazelnut tissue-culture medium optimization experiment. Driver and Kuniyuki Walnut medium (DKW) salts (NH4NO3, Ca(NO3)2·4H2O, CaCl2·2H2O, MgSO4·7H2O, KH2PO4 and K2SO4) were varied from 0.5× to 3× DKW concentrations with 42 combinations in a IV-optimal design. Shoot quality, shoot length, multiplication and callus formation were evaluated and analyzed using the two methods. Both analyses indicated that NH4NO3 was a predominant nutrient factor. RSM projected that low NH4NO3 and high KH2PO4 concentrations were significant for quality, shoot length, multiplication and callus formation in some of the hazelnut genotypes. CHAID analysis indicated that NH4NO3 at ≤1.701× DKW and KH2PO4 at >2.012× DKW were the most critical factors for shoot quality. NH4NO3 at ≤0.5× DKW and Ca(NO3)2 at ≤1.725× DKW were essential for good multiplication. RSM results were genotype dependent while CHAID included genotype as a factor in the analysis, allowing development of a common medium rather than several genotype specific media. Overall, CHAID results were more specific and easier to interpret than RSM graphs. The optimal growth medium for Corylus avellana L. cultivars should include: 0.5× NH4NO3, 3× KH2PO4, 1.5× Ca(NO3)2.  相似文献   

16.
The objective of this study was to explore the long-term effects of different organic and inorganic fertilizers on activity and composition of the denitrifying and total bacterial communities in arable soil. Soil from the following six treatments was analyzed in an experimental field site established in 1956: cattle manure, sewage sludge, Ca(NO3)2, (NH4)2SO4, and unfertilized and unfertilized bare fallow. All plots but the fallow were planted with corn. The activity was measured in terms of potential denitrification rate and basal soil respiration. The nosZ and narG genes were used as functional markers of the denitrifying community, and the composition was analyzed using denaturing gradient gel electrophoresis of nosZ and restriction fragment length polymorphism of narG, together with cloning and sequencing. A fingerprint of the total bacterial community was assessed by ribosomal intergenic spacer region analysis (RISA). The potential denitrification rates were higher in plots treated with organic fertilizer than in those with only mineral fertilizer. The basal soil respiration rates were positively correlated to soil carbon content, and the highest rates were found in the plots with the addition of sewage sludge. Fingerprints of the nosZ and narG genes, as well as the RISA, showed significant differences in the corresponding communities in the plots treated with (NH4)2SO4 and sewage sludge, which exhibited the lowest pH. In contrast, similar patterns were observed among the other four treatments, unfertilized plots with and without crops and the plots treated with Ca(NO3)2 or with manure. This study shows that the addition of different fertilizers affects both the activity and the composition of the denitrifying communities in arable soil on a long-term basis. However, the treatments in which the denitrifying and bacterial community composition differed the most did not correspond to treatments with the most different activities, showing that potential activity was uncoupled to community composition.  相似文献   

17.
The effects of chronic exposure to waterborne Cd and elevated dietary Ca, alone and in combination, were examined in juvenile rainbow trout, Oncorhynchusmykiss. Fish were chronically exposed to 0.05 (control) or 2.56 μg/l Cd [as Cd(NO3)2·4H2O] and were fed 2% body mass/day of control (29.6 mg Ca/g) or Ca-supplemented trout food (52.8 mg Ca/g as CaCl2·2H2O). Cd accumulated mainly in gill, liver, and kidney. Waterborne Cd inhibited unidirectional Ca uptake from water into the gill and induced hypocalcemia in the plasma on day 40. Waterborne Cd also induced an elevated Ca concentration on day 20 in the gill tissue of trout fed the Ca-supplemented diet and a decreased Ca concentration on day 35 in the gills of trout fed the control diet. Dietary Ca protected against Cd accumulation in gill, liver, and kidney, but did not protect against the inhibition of Ca uptake into the gill or plasma hypocalcemia. When fed Ca-supplemented diet and exposed to waterborne Cd, fish showed 35% mortality, compared to 0–2% in control fish and in the Cd-exposed fish with normal Ca in the diet. Growth, on the other hand, was not affected by any treatment.  相似文献   

18.
The long-day flowering of Lemna perpusilla 6746 on an SH inhibitor-containingmedium was inhibited by the application of ammonium ion to themedium. Ammonium ion not only suppressed long-day flowering,but relieved the inhibition of vegetative growth caused by theinhibitors. Nitrite, casamino acids, glutamine and asparaginehad a similar effect, suggesting that the inhibition of long-dayflowering by ammonium ion is not a direct effect of the ion.Most amino acids, with the exception of glutamate and aspartate,also prevented long-day flowering, but their effects on vegetativegrowth varied. No qualitative differences in amino acid compositionwere observed among plants cultured on media containing nitrate,nitrite or NH44NO3as the sole nitrogen source. However, theamounts of free and total amino acids werehigher in plants fedwith nitrite or NH4NO3 than in those fed with nitrate. Thissuggests that the inhibition of long-day flowering by ammoniumand nitrite can be ascribed to increased nitrogen metabolism. Though decreased activity by SH inhibitors of nitrate reductase(SH enzyme) is assumed to result in long-day flowering by loweringthe nitrogen metabolism, lowering the nitrogen level in M mediumdid not bring about floral initiation in the absence of SH inhibitors. (Received January 7, 1975; )  相似文献   

19.
When the long-day plant Lemna gibba L., strain G3 is grown under continuous light on ammonium-free half-strength Hutner's medium (NH4+-free 0.5 H medium) growth is excellent, but flowering is severely inhibited and often is zero. Addition of 10 micromolar salicylic acid (SA) to NH4+-free 0.5 H medium quickly reverses this inhibition and leads to optimal flowering. The SA treatment also leads to a considerable reduction in the growth rate and increase in frond gibbosity. Removal of SA from the medium quickly leads to an increase in the growth rate and a large decrease in flowering. Thus, for maximal effectiveness SA must be present in the medium for the entire experiment, and the effect of SA is clearly not inductive.  相似文献   

20.
Summary In the wheat bunt fungi (Tilletia caries), the rate of teliospore germination is not only increased by light, but also by Ca(NO3)2 and KNO3 when present in the medium (Fig. 1). CaCl2 and KCl have no stimulative effect (Fig. 2). Therefore we assume, that NO 3 - is the effective ion. The indifference of NH4NO3 in the medium may be explained by an antagonism of NH 4 + and NO 3 - .Under saturated light conditions, there is no increase in the germination rate after addition of Ca(NO3)2 or KNO3 (Fig. 3). This indicates, that the effectiveness of the two external factors light and NO 3 - is not independent.The growth of germ tubes is also stimulated with Ca(NO3)2 and KNO3, but there is no influence on the sporidial development (Fig. 4).  相似文献   

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